Commit 11335a55 authored by Luciano Coelho's avatar Luciano Coelho Committed by Johannes Berg

mac80211: implement chanctx reservation

In order to support channel switch with multiple vifs and multiple
contexts, we implement a concept of channel context reservation.  This
allows us to reserve a channel context to be used later.

The reservation functionality is not tied directly to channel switch
and may be used in other situations (eg. reserving a channel context
during IBSS join).

We first check if an existing compatible context exists and if it
does, we reserve it.  If there is no compatible context we create a
new one and reserve it.

Additionally, split ieee80211_vif_copy_chanctx_to_vlans() so we can
call it while already holding the chanctx mutex.
Signed-off-by: default avatarLuciano Coelho <luciano.coelho@intel.com>
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent 77eeba97
......@@ -426,6 +426,9 @@ static void __ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
ctx = container_of(conf, struct ieee80211_chanctx, conf);
if (sdata->reserved_chanctx)
ieee80211_vif_unreserve_chanctx(sdata);
ieee80211_assign_vif_chanctx(sdata, NULL);
if (ctx->refcount == 0)
ieee80211_free_chanctx(local, ctx);
......@@ -635,6 +638,166 @@ int ieee80211_vif_change_channel(struct ieee80211_sub_if_data *sdata,
return ret;
}
static void
__ieee80211_vif_copy_chanctx_to_vlans(struct ieee80211_sub_if_data *sdata,
bool clear)
{
struct ieee80211_local *local = sdata->local;
struct ieee80211_sub_if_data *vlan;
struct ieee80211_chanctx_conf *conf;
if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_AP))
return;
lockdep_assert_held(&local->mtx);
/* Check that conf exists, even when clearing this function
* must be called with the AP's channel context still there
* as it would otherwise cause VLANs to have an invalid
* channel context pointer for a while, possibly pointing
* to a channel context that has already been freed.
*/
conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
lockdep_is_held(&local->chanctx_mtx));
WARN_ON(!conf);
if (clear)
conf = NULL;
list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list)
rcu_assign_pointer(vlan->vif.chanctx_conf, conf);
}
void ieee80211_vif_copy_chanctx_to_vlans(struct ieee80211_sub_if_data *sdata,
bool clear)
{
struct ieee80211_local *local = sdata->local;
mutex_lock(&local->chanctx_mtx);
__ieee80211_vif_copy_chanctx_to_vlans(sdata, clear);
mutex_unlock(&local->chanctx_mtx);
}
int ieee80211_vif_unreserve_chanctx(struct ieee80211_sub_if_data *sdata)
{
lockdep_assert_held(&sdata->local->chanctx_mtx);
if (WARN_ON(!sdata->reserved_chanctx))
return -EINVAL;
if (--sdata->reserved_chanctx->refcount == 0)
ieee80211_free_chanctx(sdata->local, sdata->reserved_chanctx);
sdata->reserved_chanctx = NULL;
return 0;
}
int ieee80211_vif_reserve_chanctx(struct ieee80211_sub_if_data *sdata,
const struct cfg80211_chan_def *chandef,
enum ieee80211_chanctx_mode mode)
{
struct ieee80211_local *local = sdata->local;
struct ieee80211_chanctx_conf *conf;
struct ieee80211_chanctx *new_ctx, *curr_ctx;
int ret = 0;
mutex_lock(&local->chanctx_mtx);
conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
lockdep_is_held(&local->chanctx_mtx));
if (!conf) {
ret = -EINVAL;
goto out;
}
curr_ctx = container_of(conf, struct ieee80211_chanctx, conf);
/* try to find another context with the chandef we want */
new_ctx = ieee80211_find_chanctx(local, chandef, mode);
if (!new_ctx) {
/* create a new context */
new_ctx = ieee80211_new_chanctx(local, chandef, mode);
if (IS_ERR(new_ctx)) {
ret = PTR_ERR(new_ctx);
goto out;
}
}
new_ctx->refcount++;
sdata->reserved_chanctx = new_ctx;
sdata->reserved_chandef = *chandef;
out:
mutex_unlock(&local->chanctx_mtx);
return ret;
}
int ieee80211_vif_use_reserved_context(struct ieee80211_sub_if_data *sdata,
u32 *changed)
{
struct ieee80211_local *local = sdata->local;
struct ieee80211_chanctx *ctx;
struct ieee80211_chanctx *old_ctx;
struct ieee80211_chanctx_conf *conf;
int ret;
u32 tmp_changed = *changed;
/* TODO: need to recheck if the chandef is usable etc.? */
lockdep_assert_held(&local->mtx);
mutex_lock(&local->chanctx_mtx);
ctx = sdata->reserved_chanctx;
if (WARN_ON(!ctx)) {
ret = -EINVAL;
goto out;
}
conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
lockdep_is_held(&local->chanctx_mtx));
if (!conf) {
ret = -EINVAL;
goto out;
}
old_ctx = container_of(conf, struct ieee80211_chanctx, conf);
if (sdata->vif.bss_conf.chandef.width != sdata->reserved_chandef.width)
tmp_changed |= BSS_CHANGED_BANDWIDTH;
sdata->vif.bss_conf.chandef = sdata->reserved_chandef;
/* unref our reservation before assigning */
ctx->refcount--;
sdata->reserved_chanctx = NULL;
ret = ieee80211_assign_vif_chanctx(sdata, ctx);
if (old_ctx->refcount == 0)
ieee80211_free_chanctx(local, old_ctx);
if (ret) {
/* if assign fails refcount stays the same */
if (ctx->refcount == 0)
ieee80211_free_chanctx(local, ctx);
goto out;
}
if (sdata->vif.type == NL80211_IFTYPE_AP)
__ieee80211_vif_copy_chanctx_to_vlans(sdata, false);
*changed = tmp_changed;
ieee80211_recalc_chanctx_chantype(local, ctx);
ieee80211_recalc_smps_chanctx(local, ctx);
ieee80211_recalc_radar_chanctx(local, ctx);
ieee80211_recalc_chanctx_min_def(local, ctx);
out:
mutex_unlock(&local->chanctx_mtx);
return ret;
}
int ieee80211_vif_change_bandwidth(struct ieee80211_sub_if_data *sdata,
const struct cfg80211_chan_def *chandef,
u32 *changed)
......@@ -714,40 +877,6 @@ void ieee80211_vif_vlan_copy_chanctx(struct ieee80211_sub_if_data *sdata)
mutex_unlock(&local->chanctx_mtx);
}
void ieee80211_vif_copy_chanctx_to_vlans(struct ieee80211_sub_if_data *sdata,
bool clear)
{
struct ieee80211_local *local = sdata->local;
struct ieee80211_sub_if_data *vlan;
struct ieee80211_chanctx_conf *conf;
lockdep_assert_held(&local->mtx);
if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_AP))
return;
mutex_lock(&local->chanctx_mtx);
/*
* Check that conf exists, even when clearing this function
* must be called with the AP's channel context still there
* as it would otherwise cause VLANs to have an invalid
* channel context pointer for a while, possibly pointing
* to a channel context that has already been freed.
*/
conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
lockdep_is_held(&local->chanctx_mtx));
WARN_ON(!conf);
if (clear)
conf = NULL;
list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list)
rcu_assign_pointer(vlan->vif.chanctx_conf, conf);
mutex_unlock(&local->chanctx_mtx);
}
void ieee80211_iter_chan_contexts_atomic(
struct ieee80211_hw *hw,
void (*iter)(struct ieee80211_hw *hw,
......
......@@ -756,6 +756,10 @@ struct ieee80211_sub_if_data {
bool csa_radar_required;
struct cfg80211_chan_def csa_chandef;
/* context reservation -- protected with chanctx_mtx */
struct ieee80211_chanctx *reserved_chanctx;
struct cfg80211_chan_def reserved_chandef;
/* used to reconfigure hardware SM PS */
struct work_struct recalc_smps;
......@@ -1770,6 +1774,15 @@ int __must_check
ieee80211_vif_use_channel(struct ieee80211_sub_if_data *sdata,
const struct cfg80211_chan_def *chandef,
enum ieee80211_chanctx_mode mode);
int __must_check
ieee80211_vif_reserve_chanctx(struct ieee80211_sub_if_data *sdata,
const struct cfg80211_chan_def *chandef,
enum ieee80211_chanctx_mode mode);
int __must_check
ieee80211_vif_use_reserved_context(struct ieee80211_sub_if_data *sdata,
u32 *changed);
int ieee80211_vif_unreserve_chanctx(struct ieee80211_sub_if_data *sdata);
int __must_check
ieee80211_vif_change_bandwidth(struct ieee80211_sub_if_data *sdata,
const struct cfg80211_chan_def *chandef,
......
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